One possibility is, on multi-light tail light assemblies, is a burned out bulb. Some cars have separate light bulbs for tail, brake, turn, and backup lights
The other possibility is an electrical short in the wiring. Somewhere in the miles of wires, two wires have crossed or the insulation has worn off and is shorting to the chassis. The only cure is to trace out each individual wire with a voltage meter.
Is/Are the other bulb(s) burnt out?
Two filaments in the light bulb. One is the tail light, the other is the brake light.
If it is just one brake light, the chances are good that it is the bulb. Bulbs are cheap.
Start with replacing the bulb.
because there is two filiments in the bulb one for brake and signal light and one for running light
most likely a bulb b/c if it was the fuse your other brake and signal light wouldn't work... most vehicles the brake and signal light are all in one bulb... try replacing the light bulb
tail light bulbs has two filaments inside. One for regular lights and a second for brake lights. One filament is burnt out. Change the bulb.
Yes. One switch is for the left and right brake light assemblies; and, the other is for the 'third' brake light.
Check the switch. It has a different one than the regular brake lights. the light bulb could possibly be blown
It is possible that one of the bulbs is shorting out. Try replacing the brake light bulbs, if that doesn't work, troubleshoot the brake light switch.
check your rear light bulbs. it is a two filament light and one is burned out.
The tail light/brake light bulb has two filaments. If one of the filaments is broken, you will get either only tail lights, or brake lights. If a new bulb doesn't work, then you have a broken wire or bad connection in your plug-in.